Fracture toughness and fracture behavior of CLAM steel in the temperature range of 450 °C–550 °C

2018 ◽  
Vol 501 ◽  
pp. 200-207 ◽  
Author(s):  
Yanyun Zhao ◽  
Mengtian Liang ◽  
Zhenyu Zhang ◽  
Man Jiang ◽  
Shaojun Liu
Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2509
Author(s):  
Seyed Mohammad Javad Razavi ◽  
Rasoul Esmaeely Neisiany ◽  
Moe Razavi ◽  
Afsaneh Fakhar ◽  
Vigneshwaran Shanmugam ◽  
...  

Functionalized polyacrylonitrile (PAN) nanofibers were used in the present investigation to enhance the fracture behavior of carbon epoxy composite in order to prevent delamination if any crack propagates in the resin rich area. The main intent of this investigation was to analyze the efficiency of PAN nanofiber as a reinforcing agent for the carbon fiber-based epoxy structural composite. The composites were fabricated with stacked unidirectional carbon fibers and the PAN powder was functionalized with glycidyl methacrylate (GMA) and then used as reinforcement. The fabricated composites’ fracture behavior was analyzed through a double cantilever beam test and the energy release rate of the composites was investigated. The neat PAN and functionalized PAN-reinforced samples had an 18% and a 50% increase in fracture energy, respectively, compared to the control composite. In addition, the samples reinforced with functionalized PAN nanofibers had 27% higher interlaminar strength compared to neat PAN-reinforced composite, implying more efficient stress transformation as well as stress distribution from the matrix phase (resin-rich area) to the reinforcement phase (carbon/phase) of the composites. The enhancement of fracture toughness provides an opportunity to alleviate the prevalent issues in laminated composites for structural operations and facilitate their adoption in industries for critical applications.


Author(s):  
Sergio Limon ◽  
Peter Martin ◽  
Mike Barnum ◽  
Robert Pilarczyk

The fracture process of energy pipelines can be described in terms of fracture initiation, stable fracture propagation and final fracture or fracture arrest. Each of these stages, and the final fracture mode (leak or rupture), are directly impacted by the tendency towards brittle or ductile behavior that line pipe steels have the capacity to exhibit. Vintage and modern low carbon steels, such as those used to manufacture energy pipelines, exhibit a temperature-dependent transition from ductile-to-brittle behavior that affects the fracture behavior. There are numerous definitions of fracture toughness in common usage, depending on the stage of the fracture process and the behavior or fracture mode being evaluated. The most commonly used definitions in engineering fracture analysis of pipelines with cracks or long-seam weld defects are related to fracture initiation, stable propagation or final fracture. When choosing fracture toughness test data for use in engineering Fracture Mechanics-based assessments of energy pipelines, it is important to identify the stage of the fracture process and the expected fracture behavior in order to appropriately select test data that represent equivalent conditions. A mismatch between the physical fracture event being modeled and the chosen experimental fracture toughness data can result in unreliable predictions or overly conservative results. This paper presents a description of the physical fracture process, behavior and failure modes that pipelines commonly exhibit as they relate to fracture toughness testing, and their implications when evaluating cracks and cracks-like features in pipelines. Because pipeline operators, and practitioners of engineering Fracture Mechanics analyses, are often faced with the challenge of only having Charpy fracture toughness available, this paper also presents a review of the various correlations of Charpy toughness data to fracture toughness data expressed in terms of KIC or JIC. Considerations with the selection of an appropriate correlation for determining the failure pressure of pipelines in the presence of cracks and long-seam weld anomalies will be discussed.


1988 ◽  
Vol 120 ◽  
Author(s):  
J.-M. Yang ◽  
J.-C. Chou ◽  
C. V. Burkland

AbstractThe fracture behavior of a 3-D braided Nicalon fiber-reinforced SiC matrix composite processed by chemical vapor infiltration (CVI) has been investigated. The fracture toughness and thermal shock resistance under various thermomechanical loadings have been characterized. The results obtained indicate that a tough and durable structural ceramic composite can be achieved through the combination of 3-D fiber architecture and the low temperature CVI processing.


1996 ◽  
Vol 43 (5) ◽  
pp. 643-648
Author(s):  
Hiroyuki Takemata ◽  
Tadao Iwadate ◽  
Hajime Kuromasa ◽  
Yasuhiko Tanaka

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 393
Author(s):  
Kei Maeda ◽  
Kosho Akatsuka ◽  
Gaku Okuma ◽  
Atsuo Yasumori

Fracture behavior via a flexural test for a newly found CaO–Al2O3–SiO2 (CAS) glass-ceramic (GC) was compared with that of enstatite GC and mica GC, which are well-known GCs with high-fracture toughness and machinability, respectively. By focusing on the nonelastic load–displacement curves, CAS GC was characterized as a less brittle material similar to machinable mica GC, compared with enstatite GC, which showed higher fracture toughness, KIC. The microcrack toughening mechanism in CAS GC was supported by the nondestructive observation of microcracks around the Vickers indentation using the X-ray microcomputed tomography technique. The CAS GC also showed higher transparency than mica GC due to its low crystallinity. Moreover, the precursor glass had easy formability due to its low-liquidus temperature.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Iman Sedighi ◽  
Majid R. Ayatollahi ◽  
Bahador Bahrami ◽  
Marco A. Pérez-Martínez ◽  
Andrés A. Garcia-Granada

Purpose The purpose of this paper is to study the Mode I fracture behavior of polycarbonate (PC) parts produced using fused deposition modeling (FDM). The focus of this study is on samples printed along the out-of-plane direction with different raster angles. Design/methodology/approach Tensile and Mode I fracture tests were conducted. Semi-circular bend specimens were used for the fracture tests, which were printed in four different raster patterns of (0/90), (15/−75) (30/−60) and (45/−45). Moreover, the finite element method (FEM) was used to determine the applicability of linear elastic fracture mechanics (LEFM) for the printed PC parts. The fracture toughness results, as well as the fracture path and the fracture surfaces, were studied to describe the fracture behavior of the samples. Findings Finite element results confirm that the use of LEFM is allowed for the tested PC samples. The fracture toughness results show that changing the direction of the printed rasters can have an effect of up to 50% on the fracture toughness of the printed parts, with the (+45/−45) and (0/90) orientations having the highest and lowest resistance to crack propagation, respectively. Moreover, except for the (0/90) orientation, the other samples have higher crack resistance compared to the bulk material. The fracture toughness of the tested PC depends more on the toughness of the printed sample, rather than its tensile strength. Originality/value The toughness and the energy absorption capability of the printed samples (with different raster patterns) were identified as the main properties affecting the fracture toughness of the AM PC parts. Because the fracture resistance of almost all the samples was higher than that of the base material, it is evident that by choosing the right raster patterns for 3D-printed parts, very high resistance to crack growth may be obtained. Also, using FEM and comparing the size of the plastic zones, it was concluded that, although the tensile curves show nonlinearity, LEFM is still applicable for the printed parts.


2020 ◽  
Vol 837 ◽  
pp. 139-145
Author(s):  
Ai Jun Liu ◽  
Gang Li ◽  
Ning Liu ◽  
Ke Bei Chen ◽  
Hai Dong Yang

Effect of Ti (C,N) based cermets granule on the microstructure, mechanical properties, sintering and fracture behavior of Ti (C,N) based cermets was investigated. Results show that the Ti (C,N) based cermets granules distribute in the matrix homogeneously. A nanoindentation study was performed on hard phase and binder phase in the matrix and granule. With the increase of granules content, sintering properties is worse. With the increase of granules content, transverse rupture strength (TRS) and relative density decrease gradually, while the hardness has an opposite trend. The fracture toughness increases firstly with increasing granule, and then decreases with the further increase of granules. Higher fracture toughness of the cermets is mainly owing to the crack branch and higher fracture energy of coarse granule.


2006 ◽  
Vol 20 (25n27) ◽  
pp. 4359-4364 ◽  
Author(s):  
HYUNG-SEOP SHIN ◽  
KI-HYUN KIM ◽  
SANG-YEOB OH

The fracture behavior of a Zr -based bulk amorphous metal under impact loading using subsize V-shaped Charpy specimens was investigated. Influences of loading rate on the fracture behavior of amorphous Zr - Al - Ni - Cu alloy were examined. As a result, the maximum load and absorbed fracture energy under impact loading were lower than those under quasi-static loading. A large part of the absorbed fracture energy in the Zr -based BMG was consumed in the process for crack initiation and not for crack propagation. In addition, fractographic characteristics of BMGs, especially the initiation and development of shear bands at the notch tip were investigated. Fractured surfaces under impact loading are smoother than those under quasi-static loading. The absorbed fracture energy appeared differently depending on the appearance of the shear bands developed. It can be found that the fracture energy and fracture toughness of Zr -based BMG are closely related with the extent of shear bands developed during fracture.


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